NYC-WTC_000182709

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan November 9, 2001 Indoor Air Ouality Assessmenl Page 3 Stuwesant High School (1^477) ATC Project No. 15-19125-0246

Real-Time Environmental Measurements

ATC collected one hundred and sixteen (116) sets of real-time environmental measurements consisting of one hundred and fourteen (1 14) in the school building and two (2) outdoors. All ten floors of the school were surveyed. These results are described below. Field data sheets are found in Attachment 1. Readings began at 9:00 A.M. and concluded after 1:30 P.M.

Tcinperatiire

Indoor dry bulb temperature measurements ranged from 70.7 °F to 78.3 °F. Sixty-six (66) measurements were above the range of 68 to 75°F (at 50 percent relative humidity) recommended by ASHRAE Standard 55-1992 during the heating season (wintertime conditions). These measurements were collected throughout the school building. The outdoor temperature range was 50.1 to 58.9 °F.

Jielalive Humidity

The relative humidity indoors ranged from 17.2 percent to 31.9 percent. Only four (4) measurements were within the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. The outdoor relative humidity range was 17.5 and 28.0 percent.

Carbon Dicxide Concentration

Carbon dioxide concentrations indoors ranged from 509 ppm to 1994 ppm. Thirteen (13) CO2. measurements were above the ASHRAE Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The outdoor (background) CO2 concentrations were 450 ppm. Therefore, the maximum acceptable level of CO2 at this location was 1150 ppm (background level 4- 700 ppm). The highest reading, 1994 ppm, was in Room 735. Rooms with CO2 levels above the recommended maximum were found on the 1^1, 3'"^, 4th, 5th, 6th, 7th gth and iQth floors. Levels above the recommended maximum do not indicate a health risk. Carbon dioxide measurements are used as an indicator of available outdoor air. The primary source of CO2 indoors is occupant respiration.

Carbon Monoxide Concentration

Carbon monoxide concentrations indoors were 0 - 1 ppm for all readings. These concentrations were below the NPAAQS/ASHRAE guideline of 9 ppm. The outdoor CO concentration was 0 ppm. . . ■

Rexpirabie Particulates (PM2,j)

Respirable particulate concentrations indoors ranged between 9 pg/m^ to 28 pg/nP. All of the measurements were below the NPAAQS of 65 pg/m^ 24-hour average concentration of particulate matter 2.5 micrometers or less in aerodynamic diameter. The outdoor respirable particulate concentrations were 26 and 30 pg/mA

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